A charge pump is a kind of DC to DC converter that uses capacitors for energetic charge storage to raise or lower voltage.
Charge pumps use some form of switching device to control the connection of a supply voltage across a load through capacitors. In a two stage cycle, in the first stage the capacitors is connected across the supply, charging it to that same voltage. In the second stage the circuit is reconfigured so that the capacitors is in series with the supply and the load. This multiplies the voltage across the load - the sum of the original supply and the capacitors voltages. The pulsing nature of the higher voltage switched output is often smoothed by the use of an output capacitor.
